USSEP changes LoadScreenArt\LoadScreenMaleHighElf.nif so that the Altmer mage holds an elven mace instead of a daedric sword like in vanilla. An Altmer mage could obtain a daedric weapon though, so this is not a bug fix.
I am not an expert on nif stuff. If this is another mod that changes this, just close the report. But I currently only have USSEP installed.